Effect of inflammation induced by prolonged exercise on circulating erythroid progenitors and markers of erythropoiesis.

BACKGROUND: Exercise in humans augments the mobilization of circulating hematopoietic progenitor cells (CD34(+)) from the bone marrow. We investigated the effect of inflammation on erythroid marrow activity by mobilization of erythroid progenitor cells (EPs) along with soluble markers of erythropoiesis. METHODS: Ten healthy athletes who participated in an ultradistance foot race participated in the study. Peripheral blood mononuclear cells were isolated, before (phase I), at the end (phase II), and at 48 h post-race (phase III). EPs were detected as burst colony forming units (BFU-e) and colonies were scored at day 14. Markers of inflammation (C-reactive protein, serum amyloid-A, interleukin-6, ferritin and S100B) and bone marrow activity (erythropoietin, soluble transferrin receptor and lipocalin-2) were assessed. RESULTS: An approximately three-fold decrease in BFU-e number was observed at phase II. sTfR concentrations were also decreased at phase II and remained decreased at phase III. However, EPO and lipocalin-2 concentrations reached a maximum value at phase II, with a tendency to decrease at phase III. CONCLUSIONS: These findings indicate that exercise-induced inflammation modulates bone marrow homeostasis leading to an increase in leukocyte turnover and a decrease in erythroid compartment. It appears that lipocalin-2 is the main factor that regulates the production and mobilization of EPs.

Spartathlon, a 246 kilometer foot race: effects of acute inflammation induced by prolonged exercise on circulating progenitor reparative cells.

Endothelial progenitor cells (EPCs) and the recently described circulating fibrocytes (CFs) are strongly associated with tissue repair. We investigated the kinetics of both "repair" progenitor cells in healthy athletes who participated in the "Spartahlon" ultradistance foot race (246 km continuous running exercise), which provides a unique model of inducing dramatic systemic inflammatory changes. Peripheral blood mononuclear cells (PBMCs) were isolated from 10 volunteer athletes, who completed successfully the race, before, at the end, and at 48 h post-race. EPCs and CFs were detected as endothelial colony-forming units (CFU-ECs) and as the number of adherent with a spindle-shaped morphology Collagen I(+) cells detected after 6-day culture of PBMCs, respectively. The marked increase of plasma levels of CRP, IL-6, SAA, MCP-1, IL-8, sVCAM-1, sICAM-1, thrombomodulin (sTM) and NT-pro-BNP at the end of race established acute inflammation and tissue injury. EPCs increased by nearly eleven-fold in peripheral blood at the end of the race from 44.5+/-2.5/ml to 494.6+/-27.9/ml and remained increased 428.5+/-31.5/ml at 48 h post-race (p<0.0001). The number of the fibrocytes cultured from PBMCs obtained before, at the end, and 48 h post-race did not reveal any significant difference. These findings indicate that bone marrow responses to acute inflammatory damage, induced by exhausting exercise, with a rapid release of EPCs but not CFs into circulation. Given the ability of EPCs to promote angiogenesis and vascular regeneration, we may suggest that this kind of cell mobilization may serve as a physiologic repair mechanism in acute inflammatory tissue injury.

Midterm results of a modified evans repair for chronic lateral ankle instability.

Twenty-eight ankles in 27 patients with chronic instability were treated with a modification of the Evans procedure during a 10-year period. The diagnosis was assessed by clinical evaluation and radiographic stress tests. The reconstruction procedure consists of using the peroneal brevis tendon to repair ankle instability and restore the loss of anatomic integrity of the injured structures. Twenty-five patients (26 ankles) were available at a mean followup of 99.6 months or 8.3 years (range, 28-117 months). Midterm results were evaluated using the ankle-hindfoot score of the American Orthopaedic Foot and Ankle Society, and postoperative radiographic stress tests. According to this scoring system, the current reconstruction procedure resulted in 92.64 points (range, 63-100 points). However, moderate restriction in hindfoot inversion was seen in nine patients (34.61%). Three ankles (11.5%) had a positive anterior drawer sign (> 8 mm). In five ankles (19.2%), there were mild degenerative joint changes. Therefore, the current reconstruction method led to a satisfactory clinical and functional midterm outcome shown by a numeric scale.